looking for a green stone

There many shades of green for all budgets:

Peridot
Tourmaline (and chrome tourmaline)
Green sapphire
Green grossular garnet (mint, regular or tsavorite)
Demantoid
Sphene

And the list goes on but the above are the more "common" ones.

Any idea where I can find a beautiful, good quality stone??

What kind of green are you looking for?

mint green
deep grass green
olive green
blue green

It sounds like you want a mint green because of the green amethyst you saw.  Prices are also all over the place for green stones, so what is your price range?  Do you also care about treated stones.  Green amethyst does not occur in nature.  It is irradiated to get that color. 

If you''re looking for a bright, medium green, I just had a tourmaline cut by Barry Bridgestock set (it''s in the SMTR thread) and while the pictures are not that great, the stone is absolutely gorgeous. Incredible color and cut - I would definitely ask Barry if he has others in stock right now.

I got a green stone from the same place, ACStones. It is in my avitor, and I love it.

What shade of green do you like? Most stones have a primary color (in your case green) and a secondary color. Some green stones have yellow as a secondary color, and the end result will be a lighter yellow green. Some have a little blue, which make the stone look like a bright green.

Also, you you care about the size? Some types of stones are easier to find in larger sizes than others.